The ongoing stretch of heat enveloping Arizona means highs are expected to reach 119 degrees at Phantom Ranch inside the Grand Canyon.
Jeff Stebbins with Grand Canyon National Park said there’s a 20-degree difference between the canyon’s rim and the bottom, making it even more dangerous for hikers.
“People have this impression that heat rises,” Stebbins said, “but within geologic formation like the grand canyon there's something called adiabatic heating in which heat actually stays near the bottom.”
Stebbins said the park is advising people not to hike between 10 a.m. and 4 p.m. because of the heat...